PowerPC: initial support for LE build

This patch adds initial support for PowerPC ELFv2 Little Endian
build.
libdfp: Fix endian macro check

This patch fixes some endian macros check by replacing BYTE_ORDER for
__BYTE_ORDER and BIG_ENDIAN by __BIG_ENDIAN.
libdfp: Fixes for isinfd

This patch has three changes:
1. isinfd[32|64|128] now return -1 for minux infinity
2. powerpc isinf128d now uses the isinf32.d template instead of the
   is_template.h
3. powerpc isinf32d  was simplified to check the cr0 value in C
   instead of assembly tests.
libdfp: Fixes for isfinited

This patches makes PowerPC HW DFP code return a positive integer as
other implementations. It also simplifies the is_template.h implementation
by chekcing cr0 result in C instead of assembly.
libdfp: Fix issues with getexp when exp is DECIMAL_BIAS
libdfp: Remove compiler warnings by unused variables
libdfp: Fix test-bfp-conversions segfault due recursive calls

This patch fixes some builtins used on the conversion functions and also
the recursive calls in the long double calls where long doulbe operations
are being used resulting in recursive calls generated by the compiler.
libdfp: Add support to POWER8

This patch add support to build with --with-cpu=power8. POWER8 builds
uses the Implies for POWER7.
PowerPC: fix endian issue when reading rounding mode

This patch fixes the test-round with PowerPC hardware instruction
in LE mode. It make the read endian neutral.
PowerPC: fix the numdigits for LE

This patch fixes the numdigits PowerPC implementation by setting the
decimal bias mask in a endianess neutral way. The patch fixes the
test-numdigits along with related testcases (test-printf, test-istream,
test-ostream, and test-ostream-g-spec) for LE.
libdfp: Fix compile warnings in tests